Return to KLUBNL.PL main page
| To: | <[email protected]> |
|---|---|
| Subject: | LF: Re: Alpha benchmark |
| From: | "James Moritz" <[email protected]> |
| Date: | Fri, 21 Jan 2011 20:59:00 -0000 |
| Dkim-signature: | v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1295643539; bh=MYKxsljFV/hs9GPPgvUG4hSJfrRB6P4UZMnivq4YGgY=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=W+9eV11XMjzQchxWPJN+I4AFBAlsVTpCI8pn6gRF5FgvXkAmDvJ9kjgihHqC8uHQqlo0Ww9e5z2OIEtoxRUf1BIZwLIVFuv7Vcc7AVWk+BYOmys8SM94iR9jQ+cdPVQGMxaPlc1/HqVFQfH9gWqdDARH0xPTLQdALdq2T6VHxmI= |
| Domainkey-signature: | a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=rkSLbEhKZfPyeFjbG9M8kf2msCnuFVBtlQSjbLEvfZgKPMr/5PW0WIeJxJ2pMdQYbuZTMAE3L2TPQl6eGGyGGHURMk7OtxduCdlnApEfxAoAp1rYnDChD1ZXgrpAy1Xus05TOj3ZK6XBO2mmzAw7Nb0qw5NBMN/91bWMbpu7LsE= ; |
| Domainkey-status: | good (testing) |
| In-reply-to: | <004a01cbb99f$182a38f0$0401a8c0@xphd97xgq27nyf> |
| References: | <004a01cbb99f$182a38f0$0401a8c0@xphd97xgq27nyf> |
| Reply-to: | [email protected] |
| Sender: | [email protected] |
Dear Mal, LF Group,What you suggest might be useful as a benchmark for Alpha beacon reception, but not so helpful for 9kHz reception. The problem is that the relative noise level often varies a great deal between 9kHz and 11.9kHz, so you could have good Alpha reception and poor 9kHz reception, or vice versa. Where Alpha beacon reception tests could be useful is for assesing receiver frequency stability - remembering that accuracy and stability of the order of milli-hertz or better is *essential* for 8.97kHz amateur tests. Monitoring the Alphas using spectrogram settings for DFCW-600 or slower over a period of at least several hours or preferably days is a simple way of assesing receiver drift at these levels. You can see examples at DF6NM's and DK7FC's VLF grabber pages. For assesing receive system sensitivity, and local noise levels, you really have to do it at 8.97kHz directly. A quick check is to generate a spectrogram using QRSS3 settings - the display should be dominated by QRN, which should totally mask any receiver noise. Usually there will also be at least a few spectral lines from man-made sources present, especially harmonics of 50Hz, but many others can be present too. At my QTH, levels of this man-made noise vary greatly from one day to the next, as does the QRN. Cheers, Jim Moritz73 de M0BMU |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | RE: LF: MRC, victor13 |
|---|---|
| Next by Date: | Re: LF: Alpha benchmark, Piotr Mlynarski |
| Previous by Thread: | Re: LF: Alpha benchmark, Scott Tilley |
| Next by Thread: | LF: Re: Re: Alpha benchmark, mal hamilton |
| Indexes: | [Date] [Thread] [Top] [All Lists] |